A current detection circuit formed on a semiconductor substrate has been known in the background art. For example, Patent Literature 1 discloses a configuration that a detection MOSFET is provided in parallel with an output MOSFET serving for applying a current to a load such as a coil, and the detection MOSFET mirrors an output current outputted to the load by the output MOSFET in order to perform current detection. According to the configuration of the current detection device, the detection MOSFET is formed in a size (plane area) smaller than the size of the output MOSFET. Due to the configuration, a minute detection current in which the output current is mirrored with a magnification corresponding to a ratio between the size of the detection MOSFET and the size of the output MOSFET can be detected to monitor the output current.
In the background art, it has been well known that a spiral metal wiring is formed on a semiconductor substrate so that a coil can be formed integrally on the semiconductor substrate (e.g. Patent Literature 2).